Although natural disasters are unavoidable, people can lower the loss caused by them. When an earthquake occurs, precision machines or electronic instruments can be impacted by strong acceleration, which can damage the internal components and lead to abnormal operations or loss of functions. Taiwan is located in fault zones and has frequent earthquakes. After the Fukushima nuclear disaster of Japan, the government further emphasizes the nuclear safety when earthquakes occur. The regulations are modified for raising the anti-earthquake levels for the instruments pertinent to nuclear power generation. By adding shock absorbers under the instruments, the overall anti-earthquake level can be improved without replacing the instruments. Thereby, the safety of the instruments pertinent to nuclear power generation as well as the safety of civilians can be maintained.
Shock absorbers can isolate the vibrations of the earth surface caused by earthquakes, so that the objects situated above the shock-absorbing system can encounter less impact. Shock absorbers can be installed under instruments without influencing existing instruments. The shock absorbers require almost no repair and maintenance.
A shock absorber is an anti-earthquake system with substantial flexibility. When a general earthquake occurs, a shock absorber enables the instrument carried thereon to have nearly rigid responses. Thereby, the deformation on the instruments is reduced. The probability that the internal components are damaged is significantly reduced.
In the Taiwan Patent Publication Number M283083, a multi-functional track-type anti-vibration device is disclosed. In the invention, a pair of flat and straight sliding tracks are disposed in an alternate or parallel fashion. In addition, a sliding connecting device is disposed between the two flat and straight sliding tracks. By using the functions of the elastic members in the sliding connecting device, the effects of vibration isolation and reduction and automatic recovery between the substrate and the carrying plate are provided. Nonetheless, when a vertical force exerts on the sliding tracks, the sliding tracks will be destroyed by the stress. Besides, the weights of the carrying plate and the carried objects are supported mainly by the junctions of the sliding tracks, which tend to deform by the weights. Moreover, if only two tracks are disposed, it is difficult for the carrying plate to maintain balanced. If the carrying plate tips, the track-type anti-vibration device or the carried objects will be damaged.
In the Taiwan Patent Publication Number M313692, a multi-directional multi-frequency shock absorber is disclosed. According to the invention, a sliding connecting device is disposed between the facing surfaces of the substrate and the carrying plate. In addition, the substrate has a curved concave and a unidirectional sliding track is disposed on the carrying plate. Thereby, the sliding blocks on both ends of the sliding connecting device can contact and sliding on the curved concave and the unidirectional sliding track, respectively. Moreover, the two sliding blocks of the sliding connecting device is connected by a universal bearing. Consequently, different shock-isolating/reducing frequencies and displacements can be produced in different directions. Nonetheless, similarly, there are those problems, including damages by the stress of vertical forces on the unidirectional sliding track, and deformation on the device and unbalanced carrying plate due to the smaller pivot when only a shock-absorber is disposed.
In the Taiwan Patent Publication Number 1306911, a shock-absorbing device having an exchange mechanism between static and dynamic forces is disclosed. According to the invention, one or more set of concaves is disposed on the facing surfaces of the substrate and the carrying plate correspondingly. In each set of concaves, a rollable sphere is disposed. In addition to the sphere and the concaves, a damper can be further disposed for reinforcing the shock-reducing effect. Besides, a static-force carrying member is further disposed outside the concave of the substrate. Thereby, when no earthquake occurs, the weights of the carrying plate and the carried object are supported by the static-force carrying member, preventing the problem of wear or permanent deformation on the damper due to pressure. Nonetheless, its limiting function in the horizontal direction is inferior. When the earthquake is fierce, the carrying plate may escape from the top of the substrate, leading to damage in the shock-absorbing device or the carried object.
According to the prior art, there are technologies using tracks, balls, or universal bearings, with the accompanying spring or damper, for reducing horizontal displacements of the carrying plate and achieving the shock-absorbing effect, they still have the drawbacks of inferior vertical or horizontal shock-absorbing effect and ease of tipping. Thereby, there is still room for improvement in the structure.
The present invention improves the drawbacks in the prior art and provides a shock absorber for reducing the influences of vibration. A carrying base is added between the carrying platform and the base. A first elastic member is disposed between the carrying base and the base for providing vertical shock-absorbing effect. In addition, a first limiting groove is disposed on the top of the carrying base. By using a sliding member, the relative horizontal displacement between the carrying platform and the carrying base can be reduced and thus achieving three-dimensional shock-absorbing effect. Besides, a second elastic member is disposed on the periphery of the carrying platform and connected to the bottom plate or the sidewalls. In addition to limiting the horizontal displacement of the carrying platform, the elasticity of the spring can be used to reinforcing the shock-absorbing effect in the horizontal and vertical directions. Compared with the current known shock-absorbers, the structure according to the present invention provides superior shock-absorbing effect and is more durable.